COPENHAGEN, June 13 (Reuters) - The prime ministers of Denmark and Greenland on Wednesday agreed to explore if and how Danish funding could be used to build three planned airports in Greenland.

The Danish government has been concerned that Chinese involvement in the project, as suggested by Greenland, could upset its close ally, the United States.

Greenland is a self-ruling part of the Kingdom of Denmark, and while its government decides on most domestic matters, foreign and security policy is handled by Copenhagen.

Greenland is strategically important for the U.S. military, and its ballistic missile early warning system, as the shortest route from Europe to North America goes via the Arctic island.

“It is the government’s assessment that the airport project is of a magnitude that it - depending on funding and choice of external collaborators - could have foreign and security policy aspects,” the Danish PM’s office said in a statement.

The projects would also demand large ressources from the Greenlandic economy for a number of years, the statement added.

“Therefore the prime minister and the chairman of the Greenlandic government today have agreed to uncover if and how there could be contributed to the financing of parts of the airport projects from the Danish side,” it said. (Reporting by Teis Jensen Editing by Alison Williams)